In recent years, in consideration of the global environment and the work environment, transition from a solvent base to an aqueous base progresses in various applications, including a coating material, and the required performance of an aqueous resin dispersion, which is a raw material therefor, has increased. In particular, an emulsion polymerization method has been used as a useful method for producing the aqueous resin dispersion.
However, since the emulsion polymerization method uses a surfactant, there are problems of the occurrence of foam, the decrease in water resistance of coating film, the elution of surfactant from the coating film and the like. Therefore, in Patent Documents 1 and 2, emulsion polymerization methods using a surfactant having a polymerizable group are disclosed.